Mercury 90 ignition problems

dandreye

Petty Officer 2nd Class
Joined
Oct 19, 2007
Messages
141
Hello All,

What else besides ignition parts (3 CDM modules, stator, trigger and regulator) may also need to be replaced in a 2001 Mercury 90 ELPTO engine that briefly sank in freshwater but didn't suffer a hydraulic impact? At present only cylinder #1 (top) runs steadily while 2 others behave in a weird fasion (all 3 never work together), so we suspect electrical issues (ignition). Because of the lack of diagnostic tools and good specialists in these engines in the area all we can do is order everything that could possibly go wrong and swap it.

Thanks a lot in advance,

Dmitriy
 
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Laddies

Banned
Joined
Sep 10, 2004
Messages
12,218
Re: Mercury 90 ignition problems

Sinking don't usually effect the parts to solid state ign but if you have a OHM meter here is the CDI test for your system
scan-1.jpg
 

dandreye

Petty Officer 2nd Class
Joined
Oct 19, 2007
Messages
141
Re: Mercury 90 ignition problems

Hello Laddies,

Thanks a lot, I'll pass it to the mechanic who's near the engine and if he has such tester he'll check it. The document says one CDM module can cause the other to malfunction - if so then it may be exactly what we have. I already ordered all 3 brand-new ones along with a flywheel (one of the magnets broke off on the current one, they tried glueing it but no effect), a stator and a trigger. Can you think of anything else going wrong? The mechanic said after a click the flywheel starts spinning in the opposite direction, which he's never seen before. I don't know how long it carries on like that though, perhaps just instantly and engine stalls. Does it look like early ignition? Could it be something mechanical anyway? I just have no clue what else to suspect but ignition.

Many thanks,

Dmitriy
 
Last edited:

Laddies

Banned
Joined
Sep 10, 2004
Messages
12,218
Re: Mercury 90 ignition problems

Sounds like you have covered the problem with the parts you have on order and it does sound like a ign./timing problem.
 

dandreye

Petty Officer 2nd Class
Joined
Oct 19, 2007
Messages
141
Re: Mercury 90 ignition problems

Fingers crossed.

Btw I couldn't find any power packs in my parts manual for this particular outboard model (year 2000/01). Likewise I didn't manage to find a rectifier. Not sure if they're there at all in this model.
 

dandreye

Petty Officer 2nd Class
Joined
Oct 19, 2007
Messages
141
Re: Mercury 90 ignition problems

Yeah that's the page I used in my own parts catalog to order all the parts.

Thanks a lot again.
D.
 

dinikin

Seaman
Joined
Jul 27, 2007
Messages
51
Re: Mercury 90 ignition problems

Hi Laddies. Can this diagram be used to diagnose 90HP 2stroke made in 1996.
Top coil on my motor is not putting out any sparks at the moment.
Also that diagram above is it found in a shop manual or off the shelf maint manual.
 
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